changed recommended location for path definition
changed recommended location for path definition

as .profile is not parsed if .bash_profile is defined:
http://apple.stackexchange.com/questions/14651/where-are-environment-variables-specified-when-profile-bash-login-bash-prof/14655#14655
MRtrix3/mrtrix3,MRtrix3/mrtrix3,MRtrix3/mrtrix3,MRtrix3/mrtrix3,MRtrix3/mrtrix3,MRtrix3/mrtrix3